Vehicle bogie suspension



Dec. 25, 1951 P. G. DRONG 2,579,556

VEHICLE BOGIE SUSPENSION Filed Feb. 15, 1950 M ll FIG I INVENTOR P g DRONG yFMfi AGENT Patented Dec. 25, 1951 UNITED STATESPATENT OFFICE This invention relates to vehicles having a rear,

5 Claims. 7 (Cl. 280-1045) tandem-axle bogie, and has special reference to a bogie which automatically facilitates the steering of the vehicle.

In motor truck vehicles whichhaul heavy loads, it is common practice to provide the vehicle with an auxiliary set of wheels rearwardly of, and in alignment with, the usual rear wheels to receive part of the load. Vehicles provided with such auxiliary wheels are difficult to steer, as is commonly known. The steering of these vehicles produces forces which subject parts of the vehicle to great strain when the vehicle is moving in a curved path because the rear portion of the vehicle can not pivot simultaneously on two points, that is, on each of the wheels of the bogie on the inside of the turn. Obviously, the tires of the wheels must be dragged laterally of the vehicle when a turn is made, as the tandem wheels oppose any force tending to change the direction of the vehicles travel from a straight path. This is the cause of d'iificult steering and terrific undue wear on the vehicles tires, front and rear, due to scuffing.

One of the principal objects of my invention is to overcome the steering difilculties encountered with vehicles having tandem axle rear bogies.

Another object is to eliminate the undue wear and sending of tires on such vehicles.

Another object is to provide a novel means for suspending the tandem bogie of a vehicle to permit lateral flexibility between the vehicle chassis and the bogie, thereby aiding in the steering of.

the vehicle.

Another, more specific, object is to install a tandem bogie on a vehicle so that the forward axle and wheels of the bogie may shift from side to side to facilitate the steering of the vehicle and to eliminate the dragging of the wheels when making a turn.

Another object is to provide means to turn a tandem axle vehicle in a shorter radius without the difficulties encountered in steering common tandem-axle vehicles.

A further object is to provide a simplified bogie that will lend itself to automatic or self steering, the construction comprising coil spring become more apparent as the description of my invention proceeds.

In the accompanying drawing forming a part of this application:

possibility of the springs ever coming out of T Fig. 1 is a broken top plan view of a vehicle chassis equipped with my invention.

Fig. 2 is a sectional view on the line 22 Fig.1

with parts broken away. i

Fig. 3 is a front elevational view of the truss or beam illustrating how it rests on the axle housing.

In the drawing, the reference numeral l indicates the chassis of the vehicle, 2 indicates the front axle thereof, and 3-3 indicates the front wheels thereof.

The numeral 4 indicates the housing of the foremost one of the tandem rear axles, and 5 indicates the housing of the rearmost one of the tandem rear axles. A drive shaft 6 is provided to drive the foremost axle I, and an aux-' iliary drive shaft 8 may be provided, if desired, to

drive the rearmost axle 9, all of which is conventional.

To suspend the chassis on the rear bogie, I employ a pair of trusses or equalizing beams H] which are laid across the top of the axle housings 4 and 5 in alinement with each other and the chassis. The beams are, preferably, bridge-type,

as shown. The upper faces of the beams l0 extend substantially straight between the-two axles, however, the lower faces of the beams are i built to provide the strength required to support spring supports the weight of the load, and distributes, or equalizes the load between the axles.

The spring is secured to the chassis by means of I an inverted cup or pocket I3 fixed to the chassis l immediately above the pocket II. If desired, a

second coil spring l4 may be mounted within the spring l2 to assist in supporting the load, and, preferably, this second or inner spring would be a little longer than the outer spring l2 so that it would provide the supporting means for the chassis when the vehicle is not loaded, thus providing better riding qualities for the vehicle when;

empty. Abolt 15 may be provided to extend through the base of each pocket H and I3 and through the centers of the coil springs to limit the upward movement of the chassis in relation to the beams l0, and a cushioning spring I6 is-- preferably provided to cushion the stopping action of the bolt l5. This bolt will eliminate the 3 their respective pockets or sockets unless they are purposely taken out by a mechanic.

Having the chassis thus supported I provide torque arms I! and I8 to take the torque of the rear axles I and 9 respectively. The arms I! are pivotally secured to the housing 4 as at l9, preferably directly beneath the chassis, and are pivotally connectedto the chassis as at 2B,.as by a bracketZl extending lfrom the chassis, The torque arms l8 are pivotally secured to the hous- 10 ing 5 as at 22, and t0 the chassis as at 23 by means of a bracket 24, the arms I8 being in alinement with and directly under the chassisas are the arms IT.

The forward torque arms I! are con'siderably"" longer than the rear torque arms'ria. Thisiisxdue to the fact that the foremost wheels -25 and. axle 1 are allowed to movelto one side or thebthe'r when the vehicle is turned, while the rearmost wheels26 are prevented as much as possible, from movingto one=sideidr the-" other as thevehicle is turned; the reasons ror which will be-- come apparent.

To "complete my instal l'ationil prefer to' pivotal ly mount an auxiliary torque arm 21 between the differential housing of the axle i and the I-beam' 28 Iwhich extends across= the longitudinal nielnber's ofi the chassis 1 intermediate the-pockets 1'3, 1 and af'second auxiliarytorouearm-'29 between the i I-beam 28 and the difierential housing of the axle 9. :ThseTauXiliary' torque-arms are prov-ided' td keepithehousings 4 and-i52 fror'n a.r'011inl'radi1ii whenstorque 'power or the'brakesare -applied:-' A stabilizer 30 is connected by fiexibl'e' ends --ron-1 thei housing" B to the chassis-'fthe arm being 'substantially. p'arallel with the axle: 9 r and at right angleslto thefchassis :as showns'to' prevent the lateral movement of the rearmost axle and wheels F of theiibogieefs With. :the rconstruction :her'e Fshown and i describedranvehicle :will travel down the' road in a straighirlineias usual; eventhough the rear'axle's ares-so suspende'dlthat'lateral Emov'ement' is nossi- I bletondzheti coil: springsm Thetfstabili'zer so and shont-torque armsdfl hold the rear axle and set-0f wheelserfrom p'ivoting'iin respect to the "chassis,"= howeveii 'the longtoroue arms I and the absence of wstabili'zerarmrwill permit the forward wheels and axle o'f the bogie-tomove la'terally in respect to the chassis. In order for the axles and wheels to move laterally; the equalizer ibeams l-il merely restron the axle housingsz l and 5; and the facesg of theEIbeamS iWhich"rest on the 'housing are rounded or convex/as at 3!. so watchers: is only 1 pointicontant abetween thei beams and" the hous- 55 ingsrd and 5; as shown-in Fig.3: rThis'point contact-providesthe least pcssibleiresistance so that the -axlefihousings may slide or roll or piwitun-" derthe convex: faceof the-beamflto permitthe wheels-25 and-their axle -to m'ove laterally of the" chassis-. -The slidingmovementbetween the 0on vex '--beam ends and the axlehousings" is quite 1 smailriof course howeverpit does-aid in theturn-"r. ing ofi-the vehicle intdandth rough' a curved path; Pf and absorbs or alleviates'much o'f the strain and stress=which is applie'd to parts "of the vehicle during turning. r

The" coi1''springs also-assist" in permitting the" bog ie to move or turnin respectto the'"vehicle chassis as they-cantwist and bend freely and thefeby-absorbrnuch of the excessivestrains and stresses which a're applied to parts'of the'" vehicle wher'i it"t'urne'd to and through'a" curvedpath':

present construction, the front wheels are directly in line with the rear wheels, and as they are turned to steer the vehicle, their point of contact remains in the same alinement with the rear wheels, and the tires may be scufied or dragged before the vehicle actually begins its turn, as the rear wheels have a tendency to keep going straight, and the front wheels must force the in d'ottedil-ines Fig: :1=,ibringing the: wheels of the a: vehicle into an "arcuatealinement which :makes" it much easier to negotiate the-turn withoutmcdragging tires or causing any undue-stress or strain; :Thisfzictionmakesit possible-to negotiate a much shorter turn without undue scuffingor dragging as in the-previous construction;

In addition to the above, the'fact-that the torque is arms' l 1 are r materially longerthan -:the "torque; arms '18 permits theiwheelsa25 to movelatmv era-11y of the chassis; due' 'to :the stress-bf the vehicles' turning, the wheels 26 being? held'from such lateral i movement by :their short-rtorque arms" and the stabilizer "arm 30, :thereby.* automatically putting the three'pairs of wheels'intothe-required arcuate alinement to negotiate the turntsvIt will'be noted that'this'turning action places the-wheels 25, iwhichare on the outside of the: turn, in materially: spaced relation to the chassis, while the wheels 25, which are on the inside'of the turn, are closely adjacent-the chassis, the'zchassishaving twisted -on' the coil springs, and the wheels 25 having been-forced out of nor-- mal' alinement withi the wheels-"zfi due to the stress 50f turning. :iThe wheels and" chassis L automaticallyreturn 1 i to normalzaalinement' when the vehicle is turned back to a straight course 5 as they .areslead by the? torque arms l1 and tend to follow theapath'of least resistance which is, of course; in alinement withthesline' of movementof the-vehicle.

Having dzhusdescribed my invention, 'what I claim is: i i- 1. In a vehicle having a chassis and tandem rear axles'and housings therefor: means for-fsuspendingsaidfichas'sis "on said axle housings toprovide" automatic steering for the rearportion of said vehicle comprising,a pair of beams resting 'a'cross said housings 'in spaced parallel relation, said beams having their central portionr'ex tending below the axis -of said axles", a pocket'in said chassis above each of said beams; I a pocket in the .centralportiont of. each: 'of 'said fbeamsi-in alinement with said chassiszapockets and e'x-wtending to the"lowermost extremity of said 2. In a vehicle'ya chassisgitandemtrear axles and housings therefor and means for suspending 'saide chassis -on saidaxle housings compris ing, a pair of beams extendingiacrossisaid axle housings in spaced substantially parallel relation, a coil spring extending between the central portion of each of said beams and the portion of said chassis immediately thereabove, said springs being free to flex laterally, and torque arms extending from said housings to said chassis to com trol the relation of said axles to said chassis, and said beams being underslung so that said springs may have their base below the center of said axles.

3. The structure as set forth in claim 1 and the foremost ones of said torque arms being longer than the rearmost ones of said arms to permit the foremost axle to move laterally of said chassis.

4. Means to facilitate the steering of a vehicle having a chassis and a pair of tandem axles at the rearmost end thereof comprising: equalizer beams extending between said axles in spaced substantially parallel relation to each other, said beams having a loose engagement with said axles whereby they may pivot in at least three directions with relation to said axle, a coil spring extending between each of said beams and said chassis, said springs being free to flex laterally between said chassis and said beams, means to permit the lateral movement of the foremost one of said axles in respect to said chassis, and means to prevent lateral movement of the other of said axles in relation to said chassis, said engage ment of said beams with said axles comprising a convex face on said beams in engagement with portions of said axles at substantially right angles thereto so that said beams maypivot in relation to said axles in at least three directions.

5. In a vehicle, a chassis, tandem rear axles and housings therefor and means for suspending said chassis on said axle housings comprising, a pair of beams extending across said axle housings in spaced substantially parallel relation, a coil spring extending between the central portion of each of said beams and the portion of said chassis immediately thereabove, said springs being free to flex laterally, and torque arms extending from said housings to said chassis to control the relation of said axles to said chassis, and said beams having their ends which engage said housings convex so that only point contact is made between said housings and said beams and whereby the point of contact of said ends on said housings may move laterally of said housings and said ends may pivot in more than two directions on said housings.

PETER G. DRONG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,017,001 Hocking Oct. 8, 193:: 2,103,381 Perkins et a1. Dec. 28, 1937 2,193,567 Pointer Mar. 12, 1940 2,360,619 Peterman .Oct. 17, 1944 2,361,166 Ayers Oct. 24, 1944 2,403,833 Spangler July 9, 1946 2,456,719 Martin Dec. 21, 1948 2,493,004 Mackie Jan. 3 1950 

